Circumferential bleed valve



Oct. 9, 1962 A. HASBROUCK ETAL 3,057,541

CIRCUMFERENTIAL BLEED VALVE Filed June 3, 1958 THOMPSON INVENTORS AUGUSTUS HASBROUCK RANSOM ATTORNEY Patented Get. 9, 1962 3,057,541 CIRCUMFERENTIAL BLEED VALVE Augustus Hasbrouck, Middletown, and Ransom S.

Thompson, Middle Haddam, Conn., assignors to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed June 3, 1958, Ser. No. 742,461 8 Claims. (Cl. 230-414) This invention relates to a valve structure and is particularly adapted for a bleed valve for use in multistage axial flow compressors in a gas turbine powerplant.

Valves of this type when in use must allow a large flow of bleed gas when the valve is open but must be easily and quickly closed to cut oif the bleeding when there is no longer necessity for it. Accordingly, in the present invention the valve is in the form of a ring extending around a portion of the axial flow compressor and adapted to be moved axially in closing or opening the ports in the cornpressor wall.

A bleed valve in the form of an axially movable ring but located internally of the compressor is described and claimed in a co-pending application of Shoup, Serial No. 738,177, filed May 27, 1958 and having the same assignee as the present application. One of the principal features of the present invention is a valve of somewhat the same character but located externally of the compressor. With this arrangement it is possible to locate the bleed valve between any two successive stages of the compressor and to collect the bleed air for use externally of the powerplant.

One feature of the invention is an arrangement by which to adjust the supporting brackets for the movable valve in such a way that variations in tolerance of the parts may be compensated for thereby to assure free movement of the valve in opening or closing the bleed ports.

Other features will be apparent from the specification and claims and from the accompanying drawing which illustrates an embodiment of the invention.

FIG. 1 is a fragmentary sectional view through a portion of the wall of an axial flow compressor, the section being substantially along the line 11 of FIG. 3.

FIG. 2 is a bottom view of the structure of FIG. 1.

FIG. 3 is a developed bottom view of a portion of the compressor case showing the mechanism to cause the entire ring to move axially.

The invention, as shown, is applied to a multistage axial flow compressor in which the casing 2 supports a plurality of rows of vanes 4'and 6 with a row of blades 8 adjacent of each row of vanes. Only one row of blades is shown. Axial flow compressors of this general type are described and claimed in Savin 2,747,367.

The casing 2 in the particular arrangement shown has an inner wall 10 and an outer wall 12, the latter having a circumferential row of openings 14 for the escape of bleed air therethrough. The inner wall 10 supports the rows of vanes 4 and 6 and may be made up of several independent rings 10a and 1012, one for each row of vanes. The portion of the ring 10a and 10b that supports the associated row of vanes consists of two radially spaced concentric sleeves 16 in which the vane ends are securely positioned. The ring 10a or 10b may have a radial flange 18 at one end for attachment to or in engagement with the outer wall 12 and for supporting the ring 10a or 1012 within, concentric to and radially spaced from the outer wall.

The ring 10a extends downstream from the row of vanes 4 supported by this ring, to overlie the tips of the rotor blades 8 and to engage and be piloted'by the ring 10b, as shown. Between the vanes 4 and the adjacent blades 8 the ring 10a has therearound a valve ring 20 which is movable axially to uncover a circumferential row of openings 22 through the ring 10a. This ring has a cylindrical outer surface 24 on which the valve ring 20 is slidable and through which the openings 22 extend.

The valve ring 20 is moved axially to uncover the openings 22 through the medium of a plurality of links 26 circumferentially spaced about the periphery of the compressor case. One end of each link is pivoted on a radial pin 28 in the ring 20 and the other end of the link is mounted to turn on a stud 30 or 30a pivoted On a radial axis in'a bracket 32 attached to the outer compressor case 12. As best shown in FIG. 1, the link 26 is preferably pivotally mounted on a transversely extending pin 34 in the radial stud 30a in order to accommodate the movement of the outer end of the link as the latter rotates about the stud 30a. It will be apparent, as best shown in FIGS. 2 and 3, that movement of the links 26 about the axis of the studs 30 and 30a will cause a circumferential and also an axial movement of the valve ring and with all of the links 26 in substantially parallel relation the entire ring 20 will be caused to move axially as a unit.

In order to cause the opening and closing of the valve ring 20 the studs 30a have mounted on their outer ends a lever 36, the free end of which is connected to a link 38 and the latter is in turn connected to the piston rod 40 to an actuator 42. This actuator is the conventional piston and cylinder arrangement by means of which the piston rod can be moved selectively in either direction by the admission of actuating fluid to one end of the cylinder and simultaneously venting the opposite end. One of the problems presented by this arrangement is the mounting of all of the links 26 so that there will be no binding as the series of links pivot. T o accomplish this the bracket 32 is held as by bolts 44 to a boss 46 forming essentially an integral part of the casing. The bolts 44 engage in openings 48 in the bracket 32 which are larger than the bolt so that the bracket is free to move a small amount in a plane at right angles to the axis of the stud 30 or 30a. One circumferentially extending surface 56 of the bracket 32 extends parallel to a cooperating surface on a projection 52 on the boss 4-6.

. When the device is being mounted the valve is moved into its fully closed position and appropriate shims 54 are positioned between the surface 50 and the projection 52 to accommodate the variations from one actuator arm or link 26 to the next axial location of the brackets 32. One bracket 32 is then bolted solidly to the supporting boss and the valve is moved to its open position. Resulting variations in the tangential position of the other actuating link brackets are accommodated by circumferential movement of the brackets on the bosses and the remainder of the brackets are then bolted solidly.

As best shown in FIG. 1, the cylindrical surface 24 has a groove 56 to receive a ring seal 58 engageable by the valve ring 20 and at the opposite side of the row of openings 22 the obliquely positioned surface 60 on the inner wall 10a supports a packing 62 for engagement by the inner edge of the radially extending end surface 64 on the valve ring. The packing is held by a ring 66 bolted to the casing 2.

From the foregoing it will be apparent that when bleeding from the compressor is to take place the actuator 42, by moving the arm 36 in a clockwise direction, FIG. 2, will cause axial movement of the valve ring 20 to uncover rows of openings 22 for the discharge of the compressed fluid through the openings 22 and the openings 14 into the surrounding atmosphere. Similarly, movement of the arm 36 counterclockwise by the actuators 42 will move the valve ring into valve closing position. By providing the idler links 26 between the actuating links, the latter are connected to the arm 36, it will be clear that the entire ring is constrained to move axially without cocking even if all of the actuators do not apply the same actuating force to their respective links 26.

It is to be understood that the invention is not limited to the specific embodiment herein illustrated and described, but may be used in other ways without departure from its spirit as defined by the following claims.

1. A bleed valve for a compressor including a compressor case having an annular portion with a circumferential row of substantially radial openings therethrough and constituting a valve base, a valve ring surrounding said case at said portion and being movable on said portion in an axial direction to cover or uncover said row of openings, a plurality of similar circumferentially spaced links each link being pivoted at one end to the ring and having the other end pivoted on a fixed axis with respect to the case, and means for moving at least one of said links about the axis thereby to cause axial movement of the ring on the annular portion, said links causing uniform axial movement of the ring.

2. A bleed valve for a compressor including a compressor case having an annular portion with a circumferential row of substantially radial openings therethrough and constituting a valve base, a valve ring surrounding said case at said portion and being movable on said portion in an axial direction to cover or uncover said row of openings, a plurality of similar circumferentially spaced links each link being pivoted at one end to the ring, said other end of each link being mounted on a stud turnable on a radial axis, and a bracket supporting said stud and mounted on said case.

3. A bleed valve for a compressor including a compressor case having an annular portion with a circumferential row of substantially radial openings therethrough and constituting a valve base, a valve ring surrounding said case at said portion and being movable on said portion in an axial direction to cover or uncover said row of openings, a plurality of similar circumferentially spaced links each link being pivoted at one end to the ring, said other end of each link being mounted on a stud turnable on a radial axis, and a bracket supporting said stud and mounted on said case, said bracket having a circumferentially extending substantially radial surface and said case having a cooperating surface engageable thereby for positioning the bracket on the case.

4. A bleed valve for a compressor including a compressor casing having an annular portion with a circumferential row of openings therethrough and constituting a valve base, a valve ring surrounding said casing at said portion and being movable on said portion in an axial direction to cover or uncover said row of openings, a plurality of circumferentially spaced links pivoted at one end to the ring, said other end of each link being mounted on a stud turnable on a radial axis, and a bracket supporting said stud and mounted on said casing, said bracket being adjustable with respect to said casing in both axial and circumferential directions.

5. A bleed valve for a compressor including a compressor case having spaced concentric inner and outer walls providing an annular chamber between the walls, said inner wall having a cylindrical outer surface thereon with a plurality of openings therethrough and contituting a valve base, a valve ring surrounding and in contact with said cylindrical outer surface and being movable on said surface thereon in an axial direction to cover or uncover said row of openings, a plurality of circumferentially spaced links pivoted at one end on the ring, a plurality of circumferentially spaced brackets mounted on the outer wall of the case there being one bracket for each link on which the other end of the associated link is pivoted, all of said links being located between the Walls of the case in said annular chamber.

6. A bleed valve for a multistage axial flow compressor including a compressor casing having axially spaced rows of vanes mounted therein and extending inwardly therefrom and a row of rotor blades positioned between adjacent rows of vanes, said casing having a row of openings therethrough substantially in alignment with the row of blades, in combination with a valve ring surrounding said casing adjacent to said row of openings and movable axially on said casing to cover or uncover said row of openings, a plurality of circumferentially spaced links pivoted at one end to the ring and having the other end pivoted on an axis fixed to the casing, and means for moving at least one of said links about the fixed axis thereby to cause axial movement of the ring on the annular portion.

7. A bleed valve as in claim 5 in which each bracket is attached to the outer wall by attachment means and in which the attachment means provides for axial and circumferential adjustment of each bracket on the case.

8. A bleed valve as in claim 5 in which one bracket carries an actuating arm located externally of the outer wall and connected to the associated link for moving the link by moving the arm.

References Cited in the file of this patent UNITED STATES PATENTS 565,848 Elmer Aug. 11, 1896 1,004,230 Balcome Sept. 26, 1911 1,623,446 Taylor Apr. 5, 1927 1,929,157 Waller Oct. 3, 1933 2,458,198 Poole Jan. 4, 1949 2,741,423 Lombard Apr. 10, 1956 2,762,559 Faught Sept. 11, 1956 2,785,848 Lombard et al Mar. 19, 1957 2,819,836 Eberla Jan. 14, 1958 2,823,700 Christensen Feb. 18, 1958 2,850,227 Wheatley Sept. 2, 1958 2,858,062 Allen Oct. 28, 1958 2,861,774 Buchi Nov. 25, 1958 2,863,601 Torell Dec. 9, 1958 FOREIGN PATENTS 606,328 Great Britain Aug. 11, 1948 757,230 Great Britain Sept. 19, 1956 1,012,339 France Apr. 16, 1952 

